Electrode holder for arc lamps



1951 E. R. SUTTLE 2,580,137

ELECTRODE HOLDER F OR ARC LAMPS Filed June 15, 1950 25 v v SQ 26 3OPING/.9 w ej FIG. IO FIG. I l

FIG. l2

- 26 EUGENE R. SUTTLE INVENTOR. 36 BY A TTORNEV Patented Dec. 25, 1951UNl'PED PATENT OFFICE nnno rn'omnnonnnneroa ARO'LAMPS Eugene (Su'ttle,Wichita, ,Kans..

ap lauded-nine 1:5, 1950, S'rial- No;168C302 This invention?relates-:egenerally to" arc'--lamps, and more particularly to auxiliaryeleetrode holders-for such -'lampshol'ders which will make possible thesubstantially :'complete usenof'iipar It is the chief object of thisinvention to :provide arc lamp users with an auxiliary extensionelectrode holder which makes it possible for an arc'lampto' burnbothpositive and-negative electiazllyfburned .electro'deswvhich.itfhascipreviousl'y trodes until they are-only'l inch long,- thus'efbseen necessary tovdi's'card;

As is; well :known 'to those familiarrwithl-this art; thetworcarbonelectrodes r in econventio'nal arcvlamps :are mounted inaxial. alignment for movement toward each other as the burning itipsdisintegrate. To accomplishthis, two opposing carriagesare'slidablyilmounted on a -track-or on guidabars sandathe outer endof-eachrel'ectrode is held in auclamp-Jwhichis racpart bfwe'achmarriages The. innerend -'of. -each: electrodev isisupia portedbya'stationary guide, the two glides-serving to. keep the -burning endsof the ael'ectrodes aligned. The guides are located a short distancefrom the arc,:-and-v as the tips ofr -the electrodes disintegrate;*themoving carriages slide -the -elec-' trodes'th-roughor along theseguides Some'of theseguidesare V-shaped, some U-shaped and some; areuof(other cross-sectional shapes-ridependingon the choice of themanufacturer. of.- the lamp. h

Considering the. amount of each electrode whic'h..is. necessarily heldin=v itsi'clamp; .the amount of each electrode which lies in its guide,and therequired spacingof the arc'tromaeacli guide, no electrode can-be:burned-shorter than about 2% ,incheswithiarc lamps presently available.With a negative electrode having an original lengthof -9 inchesthisLmeans that only apeproximately 72% of it is usable -inthe.:lamp.

When such are lamps are used'incommercial motion picture projectingmachines; the.:e1ectrode' burning .rateiand the time required to projectatleastone double reel. of. film .are two .addi tionalfactors .whichk.enter. intotheeprob'lem. Since a. standard negative .electrode burns atthe rate of about 2 inches inidminutes, .and since the operator .mustrhavea continuous-rzarc for abdut minutes torunone reel-of filmit isevident that the operator vmust ha-veanegative electrode in his lamp atleast 4 /2" long when. he starts projecting ashort feature or newsreelor he will be unable .to run the rollof film continuously. Negativeelectrodes-Jess than 4% inches long are therefore discarded by projectoroperators. Disposing of a. 4 inch usedelectrode whichwasonly. 9incheslong when new" means a ldssof approximately. 45%, and.a-iconsequent increased cost fornegative electrodes c-periyear Asimilar condition exists. with relationto the slower burningpositiveelectrodes;

fec-ting a-very material reductionz'in: the "total cost of electrodes.-

It is an additional important --ob ect of the invention to provide anauxiliary electrode holder which will not cause mis al-ignment of either,ele'ctrode' as the holder passes into 'andacross theelectrodegui'depand which willfreely pass through most; if not all,present electrode guides without changing the vertical or horizontalposition. of theelectrode which it carries, vand without the necessityof modifying thecross sectional shape of the guide:

The invention,- together with other objects attending its production,will be more clearly understoodwhen thefollowingdescription is readinwconnection with the accompanying drawings, in which Fig-1 is a sideschematic viewof the working parts of a standard are projection lampwith the carbon electrodes shown in broken'lines;

Fig. 2 is aninverted perspective view 'of apreferredform of electrodeholder. embodying this invention;

Figs.-3 and 4 are top andbottom views respectively :of the holder;

- Fig. 5 is a right side view-ofthe holder mounted in aconventionalclamp'of an arc lamp assembly, theclamp being shown.fragmentarily;

Fig. dais a left side view of .the holder, th broken-lines indicatingthe relative position oc-'- 'cupied-by ana electrode when clamped in theholder; 7

Fig. 7 is anend viewof the holder taken looking directly into theelectrode clamping end;

Fig; 8 is a lateral section takenvalong the line -88 of 5;

Fig. 9 is -a='sectional viewtaken along the line 9-4! of Fig.-3,'andillustrates thecomplemental shape of the buttend of a conventionalelectrode and-theele'ctrode holdingsocket in th'eholder;

and,

Figs. 10, 11, and 12 iare end views of the holder operatively associatedwith three types of standard or conventional electrode guides; and

Fig; l3'is :anend view of a difierent type of holder embodying the"invention, operatively associated with a standard guide.

The standard lamp assemblyshown in Fig. 1 includes anindependentlysupported Itrack I5,'a traveling/negative electrodecarriage l 6 anegative electrode clamp I! which is a part of and travelswith the carriage l6, and a stationary negative electrode guide l8 whichserves to support and position the burning end of the electrode duringlamp operation. The assembly also includes a traveling positiveelectrode carriage IS, a positive electrode clamp 20 which is a part ofand travels with the carriage l9, and a stationary but adjustablepositive electrode guide 2| mounted on a-supporting standard 22.

The two carriages l6 and l 9 are suitably power driven, and areautomatically moved slowly toward each other during operation of thelamp to compensate for the slow disintegration of the two electrodes atthe arcing point. The electrodes 23 and 24 slide through the guides l8and 2| respectively, as the carriages move toward each other. The speedof movement of the carriages is coordinated, each moving at a rateequivalent to the burning rate of its respective electrode. The guidesl8 and 2| are ordinarily set from 2 /2 to 3 inches apart, and the arcingtakes place approximately midway between them during operation of thelamp. This spacing prevents are heat from melting or otherwise damagingthe guides, and necessitating their replacement. When either of theelectrode clamps I! or approaches its respective electrode guide l8 or2|, the operator replaces the electrode at the first opportunity, toprevent interruption of his projection of a subsequent roll of film.The, partially burned electrode is discarded.

After an electrode has been partially burned and replaced, the discardedportion may be placed in the holder of this invention and burned.

The embodiment of the invention illustrated in the drawing includes anelongated shank 25, which is preferably the same cross sectional sizeand shape as the electrode, and can thus be easily received and securedin the clamps l! or 20. It also includes an integral electrode clampinghead, designated as a whole by the numeral 26.

The head 26 is divided longitudinally by a saw cut into two cooperatingelectrode clamping jaws 21 and 28, both of which are integral with theshank 25, but are movable slightly toward each other due to the inherentresilience of the steel of which the holder is made. An elongated socket29, of substantially the same cross sectional size and shape as theelectrode to be held, is cut longitudinally into the free end of thehead 26, part of the socket being formed in each of the jaws 21 and 28.The axis of the socket should coincide with the longitudinal axis of theshank 25. As shown in Fig. 9 the inner or blind end of the socket isshaped to receive the butt end of the electrode so that thecorresponding surfaces of both the electrode and holder aresubstantially continuous.

The outer side surface of the jaw 2'! lies in a plane which is tangentto the cylindrical surface of the shank 25. The surface 3| of the jaw 28also lies in a plane which is tangent to the surface of the shank 25,and the two surfaces 30 and 3| lie in planes which preferably intersecteach other at an inclined angle of 60, the reason for which will beherein explained.

The two jaws 21 and 28 are provided with aligned transverse holes toreceive a clamping screw 32, as clearly shown in Fig. 8. The bored holein the jaw 28 is slightly larger in diameter than the screw 32 and issmooth walled to permit the screw to turn freely therein. The hole injaw 21 is threaded. Thus, when the screw is tightened, the two jaws 21and 28 are drawn toward each other, and exert a clamping force on thatend of the electrode which is seated in the socket 29.

Figs. 10 to 12 inclusive illustrate the reason for forming the holderhead 26 in the cross sectional shape described, with particularreference to the angle between the surfaces or faces 30 and 3!. Thepurpose is to permit the holder to pass through electrode guides ofvarying cross sectional shapes without causing the electrode tomis-align either laterally or vertically with respect to the otherelectrode.

Fig. 10 shows the described holder passing through a guide 33 whoseinside or electrode contacting surfaces diverge at an angle of 60. Itwill be seen that if the shank 25 of this holder is properly oriented atthe time it is inserted in either of the clamps I! or 20, the surfaces30 and 3| will contact and slide along the diverging inside surfaces ofthe guide 33 as the holder and its partially burned electrode are movedlongitudinally by'the carriage, and that the contact of the holdersurfaces with the guide surfaces will not in any way affect the straightline travel of the electrode 23 clamped in the holder. This is truebecause the surfaces 30 and 3| of the holder are tangent to the surfaceof the electrode 23 as well as to the shank 25, and diverge at the sameangle as the inside surfaces of this particular guide.

Fig. 11 illustrates the holder and its electrode 23 passing through whatis commonly known as a type guide 34. With this type guide the holdershank is oriented in the clamp I! so that the surface 30 aligns with oneinside surface of the guide. The partially burned electrode, the holderhead 26, and the shank 25 may then pass through the guide withoutaltering the straight line travel of the electrode,.and withoutdisturbing its alignment with its cooperating electrode.

Fig. 12 shows a guide 35 having a still difierent cross sectionalconfiguration. When the holder is used with this type of guide, theholder shank 25 is oriented in the electrode clamp 2!; to position thesurface 30 in the same plane as the horizontal surface 36 of the guide.Thus as the lamp carriage moves the holder and its electrode 24 slowlytoward the arcing point, the head 25 of the holder glides smoothly overthe supporting surface of the guide without in any way disturbing thealignment of the burning electrodes.

Fig. 13 illustrates a slightly different embodiment of the inventionassociated with a 90 guide. It is identical in construction to theholder described, except for the cross sectional shape of the jaws 38and 31, and the relative location of the electrode clamping socket inthe head, both difierences being clearly shown in this drawing figure.This type of holder works well in any 90 guide, but will not work in a60 guide 33, or

in a horizontal guide 35.

Having described the invention with sufficient clarity to enable thosefamiliar with this art to construct and use it, I claim:

A holder for a conventional cylindrical electrode of an arc lampcomprising: a cylindrical shank of the same diameter as the electrode tobe held; an enlarged integral head projecting longitudinally from oneend of the shank and laterally to one side thereof only, the oppositeside surfaces of the head adjacent the shank lying in intersectingplanes tangent to the surface of the shank, the included angle ofintersection of the two planes being between 28 and 139; a cylindricalelectrode receiving socket in said head 5 of the same-diameter as saidshank and extending to the end of the shank, the socket axis beingaligned with the shank axis, and a portion of the socket between thelines of tangency of the opposite side surfaces of the head being openthroughout the length of the socket; an axial slot in the head dividingit into two electrode clamping jaws; and means for forcibly moving saidjaws toward each other to clamp an electrode in said socket, whereby anelectrode seated in said socket abutting the adjacent end of the shankhas a socket exposed side surface forming a substantial continuation ofthe adjacent shank surface.

EUGENE R. SUTTLE.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name, Date 2,133,407 Stone Oct. 18, 19382,183,846 Robb Dec. 19, 1939 2,207,664 Granville, Sr July 9, 1940 102,215,401 McCroskey Sept. 17, 1940

